This invention relates to collapsible containers, sometimes referred to as bins, of the type which have a base which includes a portion forming the floor of the container, and upstanding side and end walls mounted on the base forming the sides of the container. The ends walls are mounted in such a way as to enable them to be positioned in stacked relation over the base, either by pivoting the walls inwardly so that they fold over the base or by detachably mounting the walls whereby they may be detached and then stacked, thus to collapse the container.
Containers of this description have a wide variety of uses. Thus, the containers range in size from relatively large capacity cargo container units for rail and shipboard handling to rather small, lightweight containers designed for commodities such as bakery goods and farm produce. Containers of an intermediate size have been widely used in the automotive and other manufacturing industries in the handling of parts and supplies used in the manufacturing process. The collapsibility of the containers facilitates their return shipping to the original supplier.
A popular form of collapsible container at the present time is one made entirely or substantially entirely from plastic materials formed by molding such as injection molding techniques. For example, the walls and base of the container may be formed from a high density polyethylene and utilizing injection molding to form the components. Containers of this description have relatively light mass and are manufactured relatively inexpensively. A collapsible container of this description forms the subject matter of Gyenge, et al., U.S. Pat. No. 4,674,647.
A problem which arises in the construction of collapsible containers is the provision of means affording access to the container interior through a side of the container. Such access is desirable since it eliminates the requirement to lean over and into the container when withdrawing product from the container. So-called drop gates have been proposed, provided in one or more walls in the container, which are pivotally mounted in place and swung to one side to open up an access opening. However, the size of such a gate is limited, if the gate is to hang vertically downwardly in an opened-up position and be out of the way. Additionally complicating the problem is that containers during use are subjected at times to considerable forces exerted outwardly on the container walls, thus to stress the walls. Thus, any construction provided permitting access through a side wall must have a construction not significantly impairing the strength of the wall. Furthermore, where access is to be provided through a side of the container, preferably it should be in such a manner as not to affect the integrity of the corner structure in the container that maintains the walls of the container in their upright position.
A general object of this invention is to provide a collapsible container with a new and improved construction for providing access to the interior of the container through a side thereof.
A related object is to provide such a container where access is provided through incorporation in the container, in a side thereof, of a removable access panel which on removal opens up an access opening closed by the panel with the panel in place.
A more specific object is to provide a collapsible container which contains a removable access panel with a novel mounting for the panel where the wall mounting the panel is braced in such a way as to retain its strength. A related object is to provide such a container where the mounting of the panel in a wall is through interfitting tongue and socket structure serving firmly to hold the access panel in the remainder of the wall.
As contemplated by this invention, the container includes opposed side and end walls pivotally mounted on a base which includes a portion forming the floor of the container. The container is collapsed by swinging the walls inwardly whereby they fold over each other over the container base. At least one of the walls is a sectional wall including an outer frame section with portions forming the perimeter of the wall along the base and side margins of the wall, and an access panel detachably mounted in this outer frame section. The access panel has downwardly projecting tongue portions along its opposite margins received within upwardly facing sockets presented by the frame section of the wall. The tongue and sockets interengage with shifting of the access panel downwardly into the frame section in a direction generally paralleling the plane of the sectional wall. With the access panel seated and in place, it becomes firmly held in a unified manner with the frame section of the wall. The wall effectively withstands stresses such as bowing stresses exerted thereon by reason of a load contained within the container. The access panel is readily removed to provide a relatively large access opening to the container interior. After removal of the contents of the container, returning of the access panel and latching it into place, the panel and frame section of the sectional wall again become unified and swingable as a unit over the base of the container to prepare the container for return shipment to the supplier.